Car safety seats for children are commercially available in a many configurations corresponding to differences in the age, weight, and size of the child being transported. Parents can choose a car seat that is not only the correct size for their child and their vehicle, but one that also suits their tastes, budget, and life style. As children grow in size and maturity level, they need different kinds of car seats. For example, a child may initially use a rearwardly facing infant car seat, then graduate to a forward facing toddler seat with an integrated harness, and finally to a belt positioning booster seat utilizing the vehicle's lap and shoulder belt system before being able to safely use the vehicle's seat belts alone.
There are many car seats on the market that can be used in multiple configurations. For instance, a forward facing car seat with an integral harness appropriate for a 20-40 pound child might accommodate a child weighing 30-100 pounds as a belt positioning booster seat with the removal of the harness and utilizing the vehicle's lap and shoulder belts. This is convenient for the care giver because it means fewer seats to purchase. Some parents choose to buy a belt positioning booster seat for their older child. Such a booster seat may be configured with a high back, such as is disclosed in U.S. Pat. No. 6,682,143, granted to Davis Amirault on Jan. 27, 2004, or can have no back at all. Older children who don't want to be seen sitting in a “baby seat” like this option and parents don't have to manage a big bulky car seat.
Currently available car seats typically have a monolithic shell, i.e. the back and seat cannot be used separately. Some car seats are designed to have a no back base option, but are configured as a separate seat fastened under the monolithic seat and back, such as is disclosed in U.S. Pat. No. 4,754,999, issued on Jul. 5, 1998, to James Kain. The problem with this configuration is the redundancy of seats; one as part of the monolithic shell, and one as a seat only.
States review and regulate restraint age limits and weight requirements. With continuing age and weight increases for recommendations in child restraint safety, a variety of restraint sizes are needed to accommodate the increasing span of children needing car seat safety restraints. The shoulder height and proper placement of belt paths are critical to the safety function of car seat restraints. As the child grows the headrest area needs to accommodate their body size and move up as they grow. Some seats are used for more than one child and the head rest area needs to move up and down to fit properly with each child. Purchasing new seats as the child grows is a costly alternative. Some seats on the market have up and down head rest adjustment but they are not always obvious or easy to operate. One example of a car seat having an adjustable head rest can be found in U.S. Pat. No. 6,623,074, granted to Ronald Asbach on Sep. 23, 2003, wherein the head rest is vertically movable on the seat back with the harness straps passing through the head rest to be adjustable therewith. Another example can be found in U.S. Patent Application Publication No. 2005/0225136, filed by William Horton and published on Oct. 13, 2005, in which the head rest is vertically adjustable relative to the seat back.
In these prior art devices, the overall length of the harness belt changes with the positional adjustment of the head rest and the appropriate relocating of the harness belt path to match the adjusted position of the head rest. To accommodate the changes in harness belt length, the car seat is provided with a belt length adjustment mechanism, usually located at the lower front portion of the car seat apparatus. Each time the position of the head rest is adjusted, the belt length adjustment needs to be manipulated to correct the length of the harness belt for proper fit of the harness on the child.
The movement of the head rest relative to the seat back or the bottom of the seat is accomplished in each of the different structural configurations within the above-identified prior art car seats though a linearly shape track. As the head rest is moved from a lowermost position to the highest position, the top portion of the head rest simply extends linearly away from the bottom of the car seat. When the seat is reclined, the head rest, of course, tips rearwardly, assuming that the car seat is placed into a forward facing orientation. This structural configuration can result in an interference between the top portion of the head rest and top of the vehicle seat, or the vehicle head rest at the top of the vehicle seat. Accordingly, it would be desirable to provide a head rest adjustment mechanism that would be operable to provide an improved clearance between the top of the car seat head rest and the top portions of the vehicle seat when the seat is reclined and the head rest is positionally elevated.
It would also be desirable to provide a harness support apparatus cooperable with an adjustable head rest for a car seat so that the overall length of the harness belt remains unchanged irrespective of the position at which the head rest is adjusted.